feat(plugins): implement Sprint 4 commands (#241-#258)

Sprint 4 - Plugin Commands implementation adding 18 new user-facing
commands across 8 plugins as part of V5.2.0 Plugin Enhancements.

**projman:**
- #241: /sprint-diagram - Mermaid visualization of sprint issues

**pr-review:**
- #242: Confidence threshold config (PR_REVIEW_CONFIDENCE_THRESHOLD)
- #243: /pr-diff - Formatted diff with inline review comments

**data-platform:**
- #244: /data-quality - DataFrame quality checks (nulls, duplicates, outliers)
- #245: /lineage-viz - dbt lineage as Mermaid diagrams
- #246: /dbt-test - Formatted dbt test runner

**viz-platform:**
- #247: /chart-export - Export charts to PNG/SVG/PDF via kaleido
- #248: /accessibility-check - Color blind validation (WCAG contrast)
- #249: /breakpoints - Responsive layout configuration

**contract-validator:**
- #250: /dependency-graph - Plugin dependency visualization

**doc-guardian:**
- #251: /changelog-gen - Generate changelog from conventional commits
- #252: /doc-coverage - Documentation coverage metrics
- #253: /stale-docs - Flag outdated documentation

**claude-config-maintainer:**
- #254: /config-diff - Track CLAUDE.md changes over time
- #255: /config-lint - 31 lint rules for CLAUDE.md best practices

**cmdb-assistant:**
- #256: /cmdb-topology - Infrastructure topology diagrams
- #257: /change-audit - NetBox audit trail queries
- #258: /ip-conflicts - Detect IP conflicts and overlaps

Closes #241, #242, #243, #244, #245, #246, #247, #248, #249,
#250, #251, #252, #253, #254, #255, #256, #257, #258

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

plugins/pr-review/claude-md-integration.md

@@ -15,6 +15,7 @@ This project uses the pr-review plugin for automated code review.
 | `/pr-review <pr#>` | Full multi-agent review |
 | `/pr-summary <pr#>` | Quick change summary |
 | `/pr-findings <pr#>` | Filter review findings |
+| `/pr-diff <pr#>` | View diff with inline comments |
 
 ### Review Categories
 
@@ -26,11 +27,16 @@ Reviews analyze:
 
 ### Confidence Threshold
 
-Findings below 0.5 confidence are suppressed.
+Configure via `PR_REVIEW_CONFIDENCE_THRESHOLD` (default: 0.7).
 
-- HIGH (0.9+): Definite issue
-- MEDIUM (0.7-0.89): Likely issue
-- LOW (0.5-0.69): Possible concern
+| Range | Label | Action |
+|-------|-------|--------|
+| 0.9 - 1.0 | HIGH | Must address |
+| 0.7 - 0.89 | MEDIUM | Should address |
+| 0.5 - 0.69 | LOW | Consider addressing |
+| < threshold | (filtered) | Not reported |
+
+With default threshold of 0.7, only MEDIUM and HIGH findings are shown.
 
 ### Verdict Rules